Despite decades on the list of "bad" fats that harm the heart, butter, on its own, is not linked to increased risk of heart disease after all, according to a recent analysis of existing research.
Eating more butter was even weakly tied to a lower risk of diabetes, the authors found.
Some people hold that butter is a "villain" while others think it is a superfood of sorts, and this review supports neither argument, said senior author Dariush Mozaffarian of the Friedman School of Nutrition Science and Policy at Tufts University in Boston.
"The findings really suggest butter is neither of those things, whether you eat a lot or none at all, there's not a big difference," he told Reuters Health.
The authors reviewed nine large studies including a total of more than 600,000 people who reported what they ate and were followed over time. Overall, 28,000 people died during the studied periods, almost 10,000 people developed cardiovascular disease and 24,000 were diagnosed with diabetes.
Consumption of butter among people in the studies ranged from none to a tablespoon (14 grams) or more daily.
Researchers found a very small increased risk of dying from any cause based on how much butter people ate. For every additional tablespoon, risk rose by 1 per cent compared to people who didn't eat butter. But that difference is so small it could be due to chance.
Risk for heart attacks, strokes and overall cardiovascular disease was similar regardless of butter intake, according to the results in PLoS ONE.
Each additional tablespoon of butter consumed was tied to a 4 per cent lower risk of developing diabetes.
"Butter's net health effect is pretty neutral," Mozaffarian said. Other daily dietary choices, like getting enough fruit and vegetables, may be more important for your health, he said.
"These results mean that we should not over-emphasise the role of butter for health, and consider its health effects against the alternative choices," said Dr. Nita Forouhi of the University of Cambridge School of Clinical Medicine in the UK who was not part of the new research.
Other studies have linked habitual butter intake to higher low-density-lipoprotein(LDL) cholesterol and potentially with weight gain over time, Forouhi told Reuters Health by email.
"This finding is not a license to eat all the butter one wants, but there is no need to single it out as being particularly unhealthy," Forouhi said.
"The findings for type 2 diabetes may be real, but they may also be limited by the complexity of doing this type of research as some people may selectively under- or over-report or avoid consumption," Forouhi said. "Or there might be alternative explanations such as the other dietary factors that could not be accounted for leading to what is known as residual confounding. For now, it is best to consider butter being neutral for diabetes risk."